Design defects occur when system components,interaction between system components,interaction between the system component and outside software /hardware ,or users are incorrectly designed.
If the user's required design is one and we designed in another way this may come under the designing defects.
In any of the defect classes throughout the testing process we may consider one thing that the users satisfaction is important.
This covers defects in the design of algorithms,control,logic,data elements,module interface description and external software/hardware/user interface description.
Design Defect Types:
Algorithmic and processing defects
Control,logic and sequence defect
Module interface description defects
Functional description defects
External interface description defects